Various clinical scenarios leading to development of the string sign of the internal thoracic artery after coronary bypass surgery: the role of competitive flow, a case series

<p>Abstract</p> <p>Background</p> <p>The left internal mammary artery (LIMA) is the choice for grafting of the left anterior descending coronary artery (LAD). One possible mechanism of the rare graft failure involve the presence of competitive flow.</p> <p>Method</p> <p>105 patients who had undergone coronary bypass grafting between 1998 and 2000 were included in this observational study. The recatheterizations were performed 28 months after the operations. The rate of patency the LIMA grafts was determined, and the cases with graft failure were analyzed.</p> <p>Results</p> <p>The LIMA graft was patent in 99 patients (94%). Six patients (6%) exhibited diffuse involution of the graft (string sign). The string sign was always associated with competitive flow as the basis of the LIMA graft involution. In one case quantitative re-evaluation of the preoperative coronary angiography revealed merely less than 50% diameter stenosis on the LAD with a nonligated side-branch of the LIMA. At recatheterization in two patients the pressure wire measurements demonstrated only a non-significant decrease of the fractional flow reserve (0.83 and 0.89), despite the 53% and 57% diameter stenosis in the angiogram. Another patient displayeda significant regression of the LAD lesion between the pre- and postoperative coronary angiography (from 76% to 44%) as the cause of the development of the competitive flow. In one instance, a radial artery graft on the LAD during a redo bypass operation resulted in competitive flow in the radial graft due to the greater diameter than that of the LIMA. In a further patient, competitive flow developed from a short sequential part of the LIMA graft between the nonsignificantly stenosed diagonal branch and the LAD, with involution of the main part of the graft to the diagonal branch.</p> <p>Conclusions</p> <p>The most common cause of the development of the string sign of a LIMA graft due to competitive flow is overassessment of the lesion of the LAD. Regression of a previous lesion or some other neighboring graft can also cause the phenomenon.</p

The Effects of Percutaneous Coronary Intervention on the Flow in Acute Coronary Syndrome Patients&mdash;Geometry in Focus

Evaluation of the effect of three dimensional (3D) coronary plaque characteristics derived from two dimensional (2D) invasive angiography images (ICA) on coronary flow determined by TIMI frame count (TFC) in acute coronary syndrome (ACS) has not been thoroughly investigated. A total of 71 patients with STEMI, and 73 with NSTEMI were enrolled after primary angioplasty. Pre- and post-PCI TFCs were obtained. From 2D images, 3D reconstruction was performed of the culprit vessel, and multiple plaque parameters were measured. In STEMI, the average post-PCI frame count decreased significantly, resulting in better flow. With regards to 2/3D parameters, no differences were found between the STEMI and NSTEMI groups. The 3D parameters in the subgroup with an increase with at least three frames resulting in worsening post-PCI flow were compared to parameters of the patients with improved or significantly not change flow (delta frame count &lt; 3), and greater minimal luminal diameter and area was found in the worsening (increased) frame group. In STEMI 2/3D, parameters showed no correlation with worsening flow, whereas in NSTEMI, greater minimal luminal diameter and area correlated with decreased flow. We can conclude that certain 2/3D parameters can predict slower flow in ACS, resulting in the use of GP IIb/IIIa receptor blocker

Quantitative MRI analysis of the brain after twenty-two years of neuromyelitis optica indicates focal tissue damage.

BACKGROUND The long-term effect of neuromyelitis optica (NMO) on the brain is not well established. METHODS After 22 years of NMO, a patient's brain was examined by quantitative T1- and T2-weighted mono- and biexponential diffusion and proton spectroscopy. It was compared to 3 cases with short-term NMO and 20 healthy subjects. RESULTS Although routine T1- and T2-weighted images appeared to be normal, quantitative T1-, T2- and diffusion-weighted magnetic resonance imaging identified areas with high diffusivity and altered relaxation time in 'normal appearing white matter' (NAWM). In such abnormal NAWM regions, biexponential diffusion analysis and quantitative spectroscopy indicated extracellular edema and axonal loss, respectively. Repeated analysis 6 months later identified the same alterations. Such patchy alterations were not detectable in the NAWM of the 3 cases with short-term NMO, and they were also not quantitatively different from the controls. CONCLUSION After NMO of 22-year duration, metabolic changes, altered diffusivity and magnetic resonance relaxation features of patchy brain areas may suggest tissue damage in NAWM that persist for at least 6 months

Aconitum alkaloid songorine exerts potent gamma-aminobutyric acid-a receptor agonist action in vivo and effectively decreases anxiety without adverse sedative or psychomotor effects in the rat

Songorine (SON) is a diterpenoid alkaloid from Aconitum plants. Preparations of Aconitum roots have been employed in traditional oriental herbal medicine, however, their mechanisms of action are still unclear. Since GABA-receptors are possible brain targets of SON, we investigated which subtypes of GABA-receptors contribute to the effects of SON, and how SON affects anxiety-like trait behavior and psychomotor cognitive performance of rats. First, we investigated the effects of microiontophoretically applied SON alone and combined with GABA-receptor agents picrotoxin and saclofen on neuronal firing activity in various brain areas. Next, putative anxiolytic effects of SON (1.0–3.0 mg/kg) were tested against the GABA-receptor positive allosteric modulator reference compound diazepam (1.0–5.0 mg/kg) in the elevated zero maze (EOM). Furthermore, basic cognitive effects were assessed in a rodent version of the psychomotor vigilance task (PVT). Local application of SON predominantly inhibited the firing activity of neurons. This inhibitory effect of SON was successfully blocked by GABA(A)-receptor antagonist picrotoxin but not by GABA(B)-receptor antagonist saclofen. Similar to GABA(A)-receptor positive allosteric modulator diazepam, SON increased the time spent by animals in the open quadrants of the EOM without any signs of adverse psychomotor and cognitive effects observed in the PVT. We showed that, under in vivo conditions, SON acts as a potent GABA(A)-receptor agonist and effectively decreases anxiety without observable side effects. The present findings facilitate the deeper understanding of the mechanism of action and the widespread pharmacological use of diterpene alkaloids in various CNS indications

Prophylactic N-acetylcysteine decreases serum CRP but not PCT levels and microalbuminuria following major abdominal surgery. A prospective, randomised, double-blinded, placebo-controlled clinical trial

Objective Our objective was to investigate whether short-term infusion of the oxygen free radical scavenger N-acetylcysteine (NAC) administered before and during extensive abdominal surgery could ameliorate the progression of early systemic inflammatory response. Design Prospective, randomised, double-blinded, placebo-controlled clinical trial. Setting Twenty-bed intensive care unit in a university hospital. Patients Following written informed consent, 100 patients were randomised into NAC and placebo groups. Three patients from the NAC group and four from the placebo group withdrew before the final analysis. Intervention The treatment group (n=47) received NAC (150 mg/kg–1 bolus followed by a continuous infusion of 12 mg/kg–1/h–1) and the placebo group (n=46) received the same volume of 5% dextrose during surgery. Measurements and results Serum procalcitonin (PCT), C-reactive protein (CRP) and microalbuminuria was monitored preoperatively, on admission to ICU, then daily during the first 3 postoperative days. For statistical analysis Mann Whitney and Chi-squared tests were used. Patients' clinical course was similar in each group as monitored by the Multiple Organ Dysfunction Scores. There was no significant difference between the two groups regarding PCT and microalbuminuria at any assessment point. Significantly lower CRP levels were found in the NAC group on days 1 and 2 (t24: median: 84.5 interquartile range: [62–120] vs. 118 [86–137] mg/l; p=0.020; t48: 136 [103–232] vs. 195 [154–252] mg/l; p=0.013, NAC vs. placebo respectively). Conclusion In this study, short-term NAC treatment decreased CRP levels, but failed to attenuate any other inflammatory response, as monitored by serum PCT and microalbuminuria. Overall, our results do not support the routine prophylactic use of NAC as a free radical scavenger in abdominal surgery